Stop me if you’ve heard any of these before:
“The warming is just part of a natural cycle.”
“We’ve been warming up since the last ice age.”
“To think humanity can influence the climate is pure arrogance.”
If you haven’t heard these arguments before, it’s clearly because you’ve never read any of the discussions attached to our climate articles. One or more of these statements appear in just about every single climate article we run, which is made even more disappointing by the fact that these arguments are ludicrously, laughably wrong. People should be embarrassed to be making them (although I’d imagine most are oblivious to that fact). In an attempt to forestall further public humiliation, I’m going to explain why, exactly, they’re such terrible arguments.
“The warming is just part of a natural cycle”
Is this a natural cycle? The most important thing to note here is that cycles imply something… well, cyclical. As in things go up, but come back down again. A look at the temperature records of the last century-plus shows that this is exactly what is not happening. Temperatures go up and flatten out at times, but they never go back down. More specifically, next month, it will be 20 years since the last time we had a month where the global temperature was below last century’s average.
The other reason that this is a nonsensical argument is that natural cycles aren’t some sort of magic—like anthropogenic factors, they influence the climate for physical reasons. In other words, if something natural is heating the atmosphere, we should see some indication of it: a change in the amount of sunlight reaching the earth, a large pool of warm water at the ocean’s surface, or something similar. Just saying “natural” doesn’t get you a free pass out of physics, and we haven’t seen anything physical that could possibly be causing the warming—nothing other than added CO2.
“We’ve been warming up since the last ice age”
OK, so maybe there’s something very subtle and longer-term going on around here. Which takes us to the second argument: we’ve been warming up since the end of the last ice age. That’s wrong from the perspective of what we know about how ice ages work. Ice ages are driven by changes in the amount and distribution of sunlight over the surface of the Earth, caused by regular variations in our planet’s orbit and axis of rotation. Since these things are so regular, we can also calculate exactly when and to what degree these changes should be influencing temperatures.